Method of and apparatus for folding sheet material



Jan. 11, 1938. M. M. BALSAM Er. 1. 2,104,727

. METHOD OF AND APPARATUS FOR FOLDING SHEET MATERIAL Filed May 20, 1936 9 She ets-Sheet 1 FIG-'- 28 33 39 32- |MM I z I I o I I I m I "'unl l ll l ll II ATT RNEY Jan. 11, 1938. BALSAM E A 2,104,727

METHOD OF AND APPARATUS FOR,FOLDING SHEET MATERIAL Filed May 20, 1936 9 Sheets-Sheet 2 Z9 36 y m '1. 99 FIG2 l 333; l a I 5 28 39 31 44 4 I l 58 U 1 M ill H?! 3 52' 5s] 5 21 i" 7 6 'll 27 I Z6 1'' 4B 10?. I II 26 1 29b I 5 i 1 46 f FIG 3 I l 07 4 I11 108 110 12 4 if [1 H 11' 1 M" l 5- i i f 43 E 110 |E: $5 2? 1 hi; I I Z 112 4 g 113 -69 1 g; Q; Z Z5 4 A" \v Q I i 112 "8 77 Q 82 so i 86 76a r 1a E Z "7 "6 73 7 83 E;

' y "1 INVENTOR 771m M- /Vw 1- M A ORNEY Jan. 11, 1938.

M. M. BALSAM-ET AL METHOD OF ,AND APPARATUS FOR FOLDING SHEET MATERI Filed May 20, 1936 9 Sheets-Sheet} ATT RNEY Jan. 11, 1 38- M. M. BALSAIV-I El AL METHOD OF AND APPARATUS FOR FOLDING SHEET MATERIAL Filed May 20, 1936 9 Sheets Sheet 4 ATT RNEY Jan. 11, 1938. M BALS ET A 2,104,727

METHOD OF AND APPARATUS FOR FOLDING SHEET MATERIAL Fil ed May 20, 1936 9 Sheets-Sheet 5 H u H- 'lmml H HI alum; 36

29 lmmum i r um mm m, Hun" "1| WWW ml- J IIIIWII- lmy ullm I l lli lllllllur 38 r i I 9 10 INVE OR AT ORNEY Jan. 11, 1938. M. M. BALSAM ET AL 2,104,727

METHOD OF AND APPARATUS FOR FOLDING SHEET MATERIAL Filed May 20, 1936 9 Sheets-Sheet 6 I l I f 109 w W fl'llllllllllllll WW -Hull!!! 107 11s 42 46 H VENTOR AT ORNEY Jan. 11, 193 8. M. M. BALSAM m- AL 2,104,727

METHOD OF AND APPARATUS FOR FOLDING SHEET MATERIAL Filed May 20, 1936 9 Sheets-Sheet 7 FIG". +4? v ATT RNEY Jan. 11, 1938. M. M.'B'ALSAM ET AL 2,104,727

METHOD OF AND APPARATUS FOR FOLDING SHEET MATERIAL Filed May 20, 1936 INVENTOR Wa BY iYan. I1, 1938.

' M; M. BALSAM ET AL METHOD OF AND APPARATUS FOR FOLDING SHEET MATERIAL Filed May 20, 1936 9 Sheets-Sheet 9 INVENTOR BY AT ORNEY Patented Jan. 11, 1938 METHOD OF AND APPARATUS FOR FOLDIN SHEET MATERIAL Maurice M. Balsa Yor Lawson I Application May 20, 1936, Serial No. 80,682

25 Claims. (01. 93-391 This invention relates to an apparatus and a method for folding sheet material and more particularly for performing a plurality of folding operations in rapid sequence.

One object of the invention is to provide an apparatus and method whereby a series of folding and forming actions may be carried out rapidly and precisely. A further object of the invention is to provide apparatus for accomplishing these results, which is simple, compact,

easy to operate,

and provided with relatively few moving parts.

A further object of the invention is to provide apparatus and method for folding a blank of sheet material into a hollow form suitable for making a bellows. A hollow blank formed in accordance with our invention may be subsequently folded to form a bellows as described in the copending application of Maurice M. Balsam, Se-

rial No. 80,683, filed May 20, 1936.

Further objects and advantage s of the invention will be more apparent from the detailed description of the embodiment thereof illustrated in the drawings, in which Figure 1 is a side elevation of a folding machine embodying the invention.

Figure 2 is a front elevation of this machine. Figure 3 is a section of one detail thereof, taken on about the line 33 of Figure 2.

Figure 4 is a vertical section on an enlarged scale, with parts of the machine shown in side elevation and taken on the line 4-4 of Figure 2.

Figure 5 is a horizontal section illustrating the folding mechanism in plan and taken on the line 5--5 of Figure 2;

Figure 6 is a front elevation par tly in section of the operating mechanism in an intermediate position;

Figure '1 is a view similar operation has been completed.

to Figure 6 with the machine in the extreme position after the folding Figure 8 is a vertical cross section of the machine in the lowermost. position,

line 8-8 of Figure '7.

taken on the Figure 9 is a horizontal sectional view taken on the line 9-9 of Figure 7.

Figure 10 is a vertical section of one detail of the machine taken on the line lU-IO of Figure '7.

Figure 11 is a horizontal section illustrating the operating shafts and cams in plan and taken on the line u u ofFigure 1.

line l2--|2 of Figure '7.

Figure 13 is a horizontal detaile d section of the cal guide 111 and William L. Lawson, New said Balsam. assignor to said same portion of the mechanism taken on the line 13-43 of Figure '7.

Figure 141s Figure 15 is a an end elevation of the end die.

vertical section illustrating one and taken on the line l6-l6 of Figure 11.

Figure 1'7 is a vertical section illustrating the operation of the foot treadle and single revolution clutch and taken on the line 11-41 of Figure v Figure 18 is a plan view of a blank adapted to be folded in the machine.

Figure 19 is a perspective of this blank in a partially folded position.

Figure 20 is a perspective of the plate to be incorporated in the folded hollow blank.

Figure 21 is a perspective of the completely folded hollow blank.

The apparatus illustrated in the drawings is supported in a side frame 25 having a plate 26 attached to its top by suitable means, such as bolts 21. The legs of frame 25 are preferably firmly secured in any suitable manner and serve to support the operating shafts; the operating mechanism for performing the folding operations is mounted on plate 26. This folding and forming mechanism comprises a die member 28, one end of which is shaped like a frustrum of a pyramid. Die member 28, as may be seen in Figure 4, is fixed to a vertically movable rod 29 by suitable means, such as the set screw 30. The rear end of posts 3| and 32, which are fixed to plate 26. Rod 29 carries at its upper end a. die section 33, spaced from the die 28 by means of the spring 34 and having'a lower surface adapted to cooperate with the upper surface of the die tersunk portions 34a in die member 28. Coun- 28 and 34b.

in die section 33 may be provided to allow the die member and die section to be brought into contact with each other upon compression ofthe spring 34.

A plate 35 is firmly attached to the tops of the rods 31 and 38, and to the top of die section 33, and is limited in its upward movement by the collar 36 on rod 29. Rod

29 is free to slide through the sleeve 29a in plate 35 and die section 33 upon compression of spring 34, and is guided by the sleeve 28b fixed to plate from.

A pair of 28 and depending therecam blocks 39 and 40 are fixed to rods 31 and 38, respectively, and these rods are adapted to reciprocate vertically in the bearing sleeves 4| and 42 with their lower ends connected by means of the tie plate 43.

Immediately below the die member 28, a lower die section 44 is mounted having an upper surface complemental to the lower surface of die 28. This lower die section 44 is resiliently supported on theplunger 45 operating in the sleeve 46 which is fixed to plate 26. Plunger 45 is normally held in uppermost position by means of the spring 41 and upward movement is limited by suitable means such as the bolt 45a. and nuts 45b. Die 28 is arranged to descend between the stationary side die sections 48 and 49 with a .clearance on each side corresponding approximately to the thickness of the material to be treated. A pair of movable slides 50 and 5| are arranged in the guide ways 52, 52 and 53, 53 for inward movement under the action of the cam blocks 39 and 40 toward the die 28. These slides move in a plane about level with the top of the side die sections 48 and 49 and are provided with openings 54 and 55, respectively, to permit free passage of the die blocks 39 and 40 and to provide for rotatably mounting the roller followers 56 and 51 which cooperate with the cam blocks. These slides have a pair of plates 58 and 59 fixed to their forward ends at an angle corresponding to the angle of the upper surface of die member 28. The slides 50 and 5| may be provided with rods.60 and 6| which slide through openings in the plates 60a and 6Iz z. The slides are thus retracted upon upward movement of the cam blocks 39 and 40 by means of the springs 69b and 6Ib on rods 60 and 6|.-

A pair of stationary plates 62 and 63 may be mounted on' the frame members 64 and 65 fixed to plate 26, at an angle parallel to the lower surface of die member 28 and below the plane 2 this lower surface when the die member 28 is in its raised position. Suitable guide members 61 and 68 may be' attached to these plates for aligning the blank 66 fore starting the folding. operation. The plates 62 and 63 are preferably cut away, as at 62a and 63a, to provide for free movement of cam blocks 39 and 40. The portion of the apparatus described thus far is operated by the vertical reciprocation of the operating rod 69 pivotally attached to the member 10, as by means of pin 1|. The upper end of the member 10 projects through the tie plates 43 andcarries a spring 12.

The lower end of operating rod 69 is pivotally connected to one arm of a bell crank 13, as by pin 14, and this bell crank 13 is pivotally mounted on the fixed shaft 15. The arm of bell crank 13, to which rod 69 is attached, carries a roller follower 16 intermediate its ends which is adapt ed to be operated by the cam 11 fixed to shaft 18. The other arm of bell crank 13 carries a roller follower 19 arranged to cooperate with cam which is also fixed to shaft 18 but which is spaced from cam 11. Shaft 18 may be rotated one revolution at a time by suitable means such as the reduction gearing 8| operating through a single revolution clutch 82 of any well known construction. For example, clutch 82 may be engaged to rotate shaft 18 by'depressing foot treadle 83 which trips a dog 84 engaging a portion of the clutch. Dog 84 is held against the clutch mecha-. nism by the action of spring 85 which, through rods 86 and 81, serves to return the foot treadle 83 to an elevated position,.and thus disengages the clutch 82 after one revolution of shaft 18,

- these folded tabs with the die sections be to fit the hole 90 in plate 88. Means may be provided for folding the ends or tabs 9|, 92, 93 and the tab 94 of double thickness over against the plate 88 when the latter is placed on the end of die member 28. These means may comprise the fixed plate 95 having an upwardly extending finger 96, the fingers 91 and 98 integral with side plates 58 and 59, respectively, and the plate 99 having a downwardly extending finger I00 and attached to the front end of the upper die section 33.

An end die I 0| may be provided for pressing 9|, 92, 93, and 94 againstplate 88, the end of the die member being recessed as shown in Fig. 14 to allow for the several fingers above-mentioned, and the protuberance 89 on die member 28. A pair of guideways I02 and I03 are fixed to plate 26 and connected at their top portions by plate I04 provided with a slot I05. -End die IOI is arranged to reciprocate horizontally between theseguides I02 and I03, and is pro vided with a pin I06 fitting. in slot I05 to limit movement of this die member.

A rocker I01 is pivotally mounted on a shaft I 08 in frame 25, and one arm of this rocker is pivotally connected to the outer end of die IN by means of the pin I01 is preferably pivotally connected to'operating rod 1 I0 by a pin III. With reference more particularly to Fig. 3, it may be seen thatthe rod I I0 is divided into two sections, the lower section I I0a extending into the housing II2 which is attached to rod section I I 0. By the arrangement of spring II3 between one end of housing H2 and the piston shaped end I I4 of rod IIOa, an operating rod is provided which has a small degree of extensibility under tension to allow for different thicknesses of material being'treated. The lower end of rod section ||0a is pivotally connected to an arm II5 by a pin H6, and the other end of this arm is pivotally mounted on shaft 15. Intermediate its ends, the arm I I5 carries a roller follower 1 which is held against cam II 8 fixed to shaft 18 by the action of spring 9 connected to plate 26 and rocker I01.

Theblank 66 to be folded by this apparatus may be fiat and of a shape adapted to be folded into the form of a truncated pyramid (Fig. 18). The end-edges of the blank are long enough to overlap each other and adhesive may be applied to one or both of the overlapping edges before folding, as illustrated in Figs. 18 and 19. A suitable adhesive may also be applied to the end tabs 9|, 92, 93, and 94 and/or one side of the plate 88.

To operate the apparatus according to the preferred embodiment of the invention, a plate 88 is fitted to the die member 28 with the plate opening 90 over the protuberance 89, and with the adhesive s de of the late. if adhesive is used,

facing outwardly. A fiat blank 66 is then laidsecures the overlapping edges together.

7 die members necessary relationship. Fingers of bell crank 13 which moves the operating rod 59 downwardly. As rod 69 is moved downwardly,

tie plate 43 and rods 31 and 38 are pulled down. Plate 35, which is attached to the top of these posts, likewise moves downwardly, pressing die section 33 down, which in turn moves die 28 down by the action of spring of die 28' pushes a section of the blank 65 down between the fixed plates Hand 63 and the fixed die sections 48 and49, and 'the remaining portions of blank 66 are thus folded up to a vertical position adjacent the sides of die 28; this position of the partially folded blank is illustrated in Fig. 19. A short downward movement of die 28 brings the central section of the blank firmly against the lower die section 44, which is also carried downwardly, holding this portion of the blank in place. Upon continued downward movement of the die 28, it is brought to a position in which its upper surface is immediately below the level of the side plates 58- and 59 fixed to slides 58 and The lower tab 92 by this time has been folded upwardly about the end of die 28 by the fixed finger 96 of plate 95. Cam blocks 39 and 89 have moved downwardly a similar distance and now begin to actuatethe slides 50 and 5| through contact with rollers 56 and 51. block 39 is preferably arranged slightly in advance of block 49 in order to move plate 58 inwardly ahead of plate 59. ,As these plates move in toward the die 28, they fold over the upstanding edges of the blank 66, and by reason of the staggered relationship of the cam blocks 39 and 49, these edges are folded over in overlapping 91 and 98,integrjal with folding plates 58 and 59, fold the end tabs 9| and 93 of the blank inwardly, simultaneously with the folding action of plates 58 and 59. The lower die section 44 and die lowermost positions and further downward movement down against the action of spring 34 to press the overlapped edges of the blank firmly together. Die section 33'is provided with a lower surface of just sufllcient width to fit between the plates 58 and 59 in the position illustrated in Fig. 9. Finger I 69 fixed to the upper die section 33 folds the end tab 94 down as the die section 33 moves downwardly. In this position the die section 33 exerts considerable pressure on the blank, depending on the strength of spring 12, and firmly Spring I2 allows some flexibility in this movement of the to obtain this pressure in order to allow for varying thicknesses of material.

In this position of the folding mechanism, cam

' H8 becomes effective to depress arm H5 and rod sections H8 and 6a. This movement of rod section H9 rocks the rocker I61 and moves the end die IOI inwardly until it presses firmly against the tabs 9|, 92, 93, and heslvely to the plate 88. I

Continued rotation of shaft 18 releases rod H6 which is returned to its original position by the action of spring 9, thus retracting the end die lol. The final portion of this single revolution of shaft 18 renders the cam 88 effective to move the shorter arm of hell crank 13 to the left (Fig. 15) thus positively lifting operating rod 69. The raising of rod 69 allows the die sections 33 l and 44, and folding plates 62 and 63 to be restored to their original positions by the action of their respective springs 34, 41, 66b and Bib. Die memz' 'ber 28 is positively restored to its original position 34. The lower portion and 8).

- the character of Cam 28 have now reached theirv of rod 69 moves the upper die section 33- use of such terms and 94 securing them adthe use of some material, such as a thermo-plas tic resin, as an adhesive. When employing such an adhesive, die section 33 and end die lili are preferably provided with internal heating means such as'electrical resistances I29 and I22 illustrated diagrammatically in dotted lines (Figs. 4 If desired, the die member 28 may also be heated by the unit i2l.

Cams 11, 88, and H8 may be suitably designed to press the adhesively, coated portions of the blank for the requisite time to secure a good bond, depending on the temperaturev of thedies and the adhesive employed. with a given thermo-plastic adhesive, a longer time is generally necessary with lower temperatures .within temperature limits such as would normally be employed, e. g., in the neighborhood of 200 F.

If a non-thermo-plastic adhesive is employed. heating of the dies will, of course, not be necessary nor will it be necessary to employ the timing arrangement of cam operating means; the apparatus may simply be operated by a foot treadle in any suitable manner. Various modifications of the embodiment described may be made within the scope of our invention as will be apparent to those skilled in the art. If it is not desired to fold the end tabs of the eral fingers for performing these operations may be readily omitted. The die 28' may be of any suitable shape, even cylindrical or conical, and the blank may be provided with end tabs of other shapes arranged to be folded and secured together in overlapping position to form a hollow article open ,only at one end. Although the die members 48 and 49 have been described as stationary or' fixed, they may be resiliently'mounted to provide for folding sheet materialv of varying hickness without binding. The terms fixed members and fixed die members used in the claims are intended to include members whichare capable of such movement, although relatively fixed with respect to the movement of the main die.

The terms and expressions which we have employed are used as terms of description and not of limitation, and. we have no intention, in the expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various. modifications are possible within the scope of the invention claimed.-

clamping an intermediate section of said blank and folding the side sections thereof with respect to said intermediate section, means for folding blank inwardly, the sev-- portions of said side sections into an overlapping position while restraining movement of the remaining portions of said side sections, and reciprocating means for synchronously operating said means by a single stroke.

3. Apparatus for folding a blank of sheet material into a hollow shape comprising means for clamping an intermediate section of said blank and folding the side sections thereof with respect to said intermediate section, means for folding portions of said side sections 'and restraining movement of the remaining portions of said side sections, means for pressing said overlapped portions together, and means for synchronously operating said means, said first named means being actuated by movement of said pressing means. v

4. Apparatus for folding a blank of sheet ma terial into a hollow shape comprising means for clamping an intermediate section of said blank and folding the side sections thereof with respect to said intermediate section, means for folding portions of said side sections and restraining movement of the remaining portions of said side sections, and a single reciprocating rod for actuating said means in synchronism.

5. Apparatus for folding a sheet of material comprising means for simultaneously clamping, movingan intermediate section of said sheet and folding side sections of the sheet with respect to said intermediate section, and means for subsequently folding the endportions of said side sections inwardly toward each other.

6. Apparatus for forming a sheet of material comprising a die, a pair of fixe mbers, means for moving said die to press an intermediate section of 'said sheet into the opening between said fixed members thusfolding side sections of said sheet about said die, and means for folding free portions of said side sections while the remaining portions of said side sections are held by said fixed members to form said sheet into a hollow blank.

7. Apparatus for forming a sheet of material comprising a die, a pair of fixed members, means for moving said die to press an intermediate section of said sheet into the opening between said fixed members thus folding side sections of said sheet about said die, means for folding free portions of said side sections about' said die and into overlapping relationship while the remaining portions of said side sections are held by said fixed members, and means for securing said overlapped portions together.

8. Apparatus for forming a sheet of material comprising a die, a pair of fixed die members spaced from each other, reciprocating means for moving said die into the space between said members to fold said sheet, and a pair of plate-like members for subsequently folding the'free ends of said sheet about said die, said reciprocating means also actuating said plate-like members.

9. Apparatus for forming a sheet of material comprising a die, a pair of fixed die members spaced from each other, reciprocating means for moving said die into the space between said members to fold said sheet, a pair of plate-like members for subsequently folding the free ends of said sheet about said die, and means for securing said folded ends together, said reciprocating means also actuating said plate-like members and said securing means.

10. Apparatus for forming a sheet of material comprising a die, a pair of fixed die members spaced from each other, reciprocating means for about said die folding an end portion of said intermediate secmoving said die into the space between said members to fold said sheet, and a pair of plate-like members for subsequently folding the free ends of said sheet about said die, said plate-like members being arranged to fold one of the free ends before folding the other of said ends and being actuated by said reciprocating means.

11. Apparatus for forming a sheet of material comprising a die, a pair of fixed die members spaced from each other, means for moving said die into the space between said members to fold said sheet, a pair of plate-like members for subsequently folding the free ends of said sheet about said die, said plate-like members being arranged to fold one of the free ends before folding the other of said ends, a movable die section for securing said folded ends together, and spring means between said die and movable die section for normally maintaining said die and die section spaced from each other.

12. Apparatus as defined in claim 7 in which the overlapped portions are pressed together by heated die means.

13. Apparatus for folding a blank of sheet ma.-

-terial into a hollow shape comprising means for clamping an intermediate section of said blank and simultaneously folding the side sections thereof with respect to said intermediate section, means for folding portions of said side sections and restraining movement of the remaining portions of said side sections, and means cooperating with said aforementioned means for folding the ends of said intermediate and side sections inwardly toward each other.

14.Apparatus for forming a sheet of material comprising a die, a pair of fixed members, means for moving said die to press an intermediate sec-' tion of said sheet into the opening between said fixed members thus folding side sections of said sheet about said die, means for simultaneously tion against one end of said die, means for folding free portions of said side sections about said die and simultaneously folding end portions of the remainder of said side sections about the end of said die, and means for securing said free portions together.

15. Apparatus for forming a sheet of material comprising a die, a pair of fixed members, means for moving said die to press an intermediate section of said sheet into the opening between said fixed members thus folding side sections of said sheet about said die, means for simultaneously folding an end portion of said intermediate section against one end of said die, means for folding free portions of said side sections about said die and simultaneously folding end portions of the remainder of said side sections about the end of said die, means for securing said free portions together, and means securing the several end portions together. v

16. Apparatus as defined in claim 15 in which said free portions and end portions are secured together by heated die means.

17. Apparatus as defined in claim 15 in which said free portions and end portions are secured together by die means provided with adjustable heating means and including means for pressing said die means against said blank for a predetermined period of time adjusted according to the temperature of said heating means.

18. The method of folding a blank of sheet material about a die comprising simultaneously clamping an intermediate section and folding side sections of said sheet with respect to said intermediate section, folding th free portions of said side sections toward each other about the die and in overlapping position while restraining the remainder of said side sections from movement, and securing said overlapped portions together.

19. The method of folding a fiat blank of sheet material into' a hollow shape comprising applying'thermo-plastic resin to an edge of said blank, folding side sections of said blank with respect to an intermediate section thereof, restraining portions of said side sections against movement while folding the free portions thereof inwardly into overlapping position with the resin therebetweemand heating and pressing said overlapped por-.

tions to secure a bonding action with said resin.

20. The method of folding a blank of sheet material about a die comprising folding side sections of said sheet with respect to an intermediate section thereof, folding an end of said intermediate section about one end of the die, folding free portions of said side sections inwardly into overlapping relation and simultaneously folding ends of the remainder of said side sections inwardly about the end of 'said die, securing said overlapped portions together, folding an end of said overlapped portions about the end of the die, and

securing said ends together.

21. Apparatus for folding a sheet of material comprising a movable die, means for folding a blank of sheet material about saiddie as the die is moved, andmeans for securing the free edges of the folded blank together, said die being moved by a resilient connection to said securing means;

'22. Apparatus for folding a sheet of material comprising a die about which said sheet is to be folded, side members for folding side sections of the sheet with respect to an intermediate section thereof, means for simultaneously folding an end of said" intermediate section about the die, means for folding free portions of said side sections and for simultaneously folding end portions of the remainder of said side sections about the die, and means for securing said free portions -togethert 23. The method of folding a blank about a die comprising folding side sections with respect to an intermediate section thereof, folding free portions of said side sections together, and folding and securing the ends of said side .and inter mediate sections to a stiffening member associated with said die.

24. Apparatus as defined in claim 15 in which said free portions and end portions are secured together by heated die means and including means for pressing said heated die means against said portions for a predetermined period of time and under a predetermined pressure adjusted in accordance with the temperature of said die means.

2 5. A method as defined in claim 18 in which the overlapped portions are secured together with a thermo-plastic adhesive by heating and pressing the portions together under a predetermined pressure and for a predetermined period of time adjusted in accordance with the temperature to which said portions are heated.

' MAURICE M. BALSAM.

WILLIAM L. LAWSON. 

